Electric hollow conductor



Jan. 3, 1933. ZAPF 1,893,120

ELECTRIC HOLLOW CONDUCTOR Filed. Jan. 50, 1929 Fig.4.

Patented Jan. 3, 1933 UNITED STATES PATENT OFFICE GEORG ZALPF, OF RIEHLERWALL, COLOGNE, GERMANY, ASSIGNOR TO FELTEN &;

GUILLEAUME CABLSWERK AGTIEN-GESELLSCHAFT, OF COLOGNE-MULHEIM', GER- MANY ELECTRIC HOLLOW CONDUCTOR Application filed January 30, 1929, Serial No. 336,233, and in Germany February 29, 1928-.

This invention relates to an improved electric hollow conductor intended for high- Voltage overhead lines.

Hollow conductors as hitherto employed are almost always provided with Supporting and carrying members. As the latter members are employed only to an extremely small extent in the conduction of current and as they considerably increase the weight of the conductor, it has already been proposed to use for the construction of the conductor exclusively flat wires which are so stranded together that the adjacent wires engage with one another. It has also been proposed to use profile wires which engage with one another in the manner of tongues and grooves. The construction first above referred to has the drawback that the circular cross section of the hollow conductor is not maintained and that the non-circular parts which may be produced lead to losses due to a corona efi'ect. The second form of construction has the drawback that the cross section of the individual profile wires, if the construction is to be such as to constitute a self-supporting rigid structure, must, for reasons of strength, he made larger than is necessary with respect to the current load.

According to the present invention, the hollow conductor is produced without using any supporting or carryin member from a single flat and wide strip o amaterial which is a good electric conductor, which strip is wound helically into a cylinder, whilst the abutting edges of the strip are folded together. The folds are produced in suitable devices similar to those which are employed in the manufacture of metal hosepipes. The folding parts which run helically around the hollow conductor form a good mechanical union, at the same time strengthening the supporting and carrying members above referred to are avoided.

The invention is illustrated, by way of example, in the accompanying drawing, in which Figure 1 shows, partly in elevation and partly in sectional elevation, the improved hollow conductor, whilst 1 Figure 2 is a cross section along the line AB in Figure 1.

The folding a is provided, as will be seen from Figure 1, in such a manner that no edges project over the surface of the conductor,

conductor to such an extent that separate supportin and carrying members are rendered super uous. Further, as in the case of such a construction the cross section of the conductor need not be made larger than is necessary for the current load, the whole of the construction is very light, so that the disadvanta es which are inherent to the two constructions of hollow conductors without the 

